Welcome back, Robert, and as always I appreciate you contributions to the conversation. But I have to respectfully disagree.
Some appellations may get lost in the shuffle, but others manage to make the breakthrough.
A generation ago, only the most serious and knowledgeable of Rhône freaks appreciated the greatness of Cornas, and so from the beginning of the 1970s to the late 1980s, the only young person who didn't leave to work elsewhere in a different calling was Robert Michel. Checked the prices recently of the top Cornas producers? And the best sites of St-Joseph are beginning to get the recognition they've long deserved.
Ditto for Bandol. Or Gauby in Roussillon.
Want something more dramatic? Who ever heard of Wicker or Pünderich? But Flick and Busch have no trouble selling their wines because they truly are top class and from demonstrably outstanding sites. If wines from Kobern aren't getting what Busch is getting for his wines from Pünderich, well, all you have to do is taste them side by side to see why.
The Southern Pfalz used to be known only for the size of its harvests of wine that supplied the lowest classes of negociants. But now some of the greatest wines of Germany are coming out of there: red as well as white. (Indeed, as some of the southern Pfalz vineyards are actually in Alsace, one scratches one's head in wonder why the Alsatians aren't producing wines of anywhere near the same quality).
Perhaps the only area held in even lower regard than the southern Pfalz was the interior Rheinhessen: it went a step further than the southern Pfalz and was planted in such atrocities as Optima. It was the trash heap of Germany. Now, producers such as Wittmann, Keller, Groebe, Battenfeld-Spanier, and others have demonstrated that they can regularly produce some of the world's greatest Rieslings -- not from slate soils, but from limestone!
Anyone ever heard of Bockenau? Not until some kid named Tim Schäfer came along and showed what could be done with its best site, and now many knowledgeable palates will tell you that he is making wines that are even greater than those of his mentor, Helmut Dönnhoff.
I certainly never would have thought of paying more than $10-15 for a bottle of wine from Umbria until I tasted Bea's wines. They're worth every penny, even if US markups can be severe.
And then there's Austria. Not only unknown, plagued by a terrible scandal. And yet, they've managed to overcome all that and earn their deserved respect.
Etc., etc.*
As for Marcillac, I've never visited and the only ones I've had have been from Matha, so I may have revelations yet to come, but based on the bottles I've purchased and drunk in the past, I fail to see the potential for great quality that the above-referenced producers and regions have demonstrated.
I do think in today's world, if you are producing top quality wines, the world will find you and within a reasonable time you will get a price that allows you to live quite decently from your work -- not at the level from even mediocre producers of Burgundy or bad producers of classified Bordeaux, but still well enough.
* A sad variant is that in some regions, such as the Languedoc, it is the medium-priced wines (which these days do allow the producers to live reasonably well) that are the best, while the high priced wines are badly spoofed. I think with time, the situation will right itself (although it may take a while -- Côte-Rôtie is largely still a mess after more than twenty years of spoofing by many producers).